Alkamin esters of para-aminobenzoic acid.



IINITEI) STATES PfiTENT OFFICE.

ALFRED EINHORN, OF MUNICH, GERMANY, ASSIGNOR TO FARBWERKE VORM. MEISTERLUCIUS 8o BRUNING, OF HOCHST-ON-THE-MAIN, GERMANY, A CORPORATION OFGERMANY.

ALKANIIN ESTERS OF PARA-AMINOBENZOIC ACID.

Specification of Letters Patent.

Patented Feb. 13, 1906.

To all whom it may concern.-

Be it known that I, ALFRED EINHORN, Dr.

Rer. Nat, professor of chemistry, a citizen of the Empire of Germany,residing at Munich, Germany, have invented certain new and usefulImprovements in the Preparation of Alkamin Esters of Para-AminobenzoicAcid, of which the following is a s ecification.

I have found that the a kamin esters of para-aminobenzoic acid may beobtained by reducing the alkamin esters of para-nitroben zoic acid. Thecompounds thus obtained, hitherto unknown, are valuable for medicinalpurposes as local anesthetics.

The alkamin esters of para-aminobenzoic acid are colorless compounds,little soluble in water, of a low melting-point, readily soluble inalcohol, ether, and benzene and of alkaline reaction on litmus. The saidesters form salts readily soluble in water to a neutral solution. Onheating with acids or alkalies the alkamin esters of para-aminobenzoicacid are decomposed with formation of para-aminobenzoic aicd and analkamin. These esters have the roperty of producinglocal anaesthesia,and t is property is not associated in their neutral reactinghydrochlorids with any irritating eflect. To prepare the said new estersof alkamins, the process may be carried out, for instance, as follows:Ten arts, by weight, of ara nitrobenzoyldiethylaminoethanol., Whic forinstance, may be obtained by heating for one day to 100 to 120centigrade paranitrobenzoylchloroethanol (obtained by heating ethylenechlorhydrin with para-nitrobenzoylchlorid) with ten arts, by wei ht, ofdieth lamin, being an oil readily soluble in ether an solidifying in thecold, are allowed to digest at a moderate temperature with thirteenarts, by weight, of tin and twenty-five parts, 4

y weight, of concentrated hydrochloric acid. From the colorless solutionthus obtained the tin is (precipitated by means of hydrogen sulfid, anon addition of sodium carbonate thepara-aminobenzoyldietliylaminoethanol is separated as an oil'which soonsolidifies. This alkamin ester crystallizes from dilute alcohol as whiteneedles, melting at 51 centigrade. With one equivalent of hydrochloricacid it forms a hydrochlorid, readily soluble in water with a neutralreaction and crystallizing from absolute alcohol in needles melting at156 centigrade.

In an analogous or different manner other alkamin esters ofpara-aminobenzoic acid may be obtained. 7

Having now described my invention, what I claim is- I. -As new products,the alkamin esters of para-aminobenzoic acid, being colorless conpounds, little soluble in. water, but readily soluble in alcohol, etherand benzene, of alkaline reaction on litmus, decom osed when heated withacids or alkalies wit formation of para-aminobenzoic acid and analkamin, forming salts soluble in water to a neutral solution whichproduces local anaesthesia without causing any irritation.

2. As a new product, the alkamin esterpara-aminobenzoyldiethylaminoethanol being a colorless compound verylittle soluble in water, very readily soluble in alcohol, ether andbenzene, solidifying in the cold and of alkaline reaction on litmus,decomposed, when heated with hydrochloric acid or sodalye, intopara-aminobenzoic acid and diethyl- -aminoethanol, forming a salt withone eguivalent of hydrochloric acid which crysta lizes needles meltingat 156 centigrade the solution of which is of anesthetic action withoutcausing irritation.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing Witnesses.

ALFRED EIN'HORN.

from I absolute alcohol in Witnesses:

ULYSSES J. BYWATER, MATHILDE K. HELD.

